Semiconductor device structure with backside contact

Abstract

A semiconductor device structure is provided. The semiconductor device structure includes a stack of channel structures and a first epitaxial structure and a second epitaxial structure adjacent to opposite sides of the channel structures. The semiconductor device structure also includes a gate stack wrapped around the channel structures and a backside conductive contact connected to the second epitaxial structure. The second epitaxial structure is between a top of the backside conductive contact and a top of the gate stack. The semiconductor device structure further includes an etch stop layer extending along a sidewall of the backside conductive contact and a bottom of the gate stack.

What is claimed is: 
     
       1. A semiconductor device structure, comprising:
 a stack of channel structures; 
 a first epitaxial structure and a second epitaxial structure adjacent to opposite sides of the channel structures; 
 a gate stack wrapped around the channel structures; 
 a backside conductive contact connected to the second epitaxial structure, wherein the second epitaxial structure is between a top of the backside conductive contact and a top of the gate stack; and 
 an etch stop layer extending along a sidewall of the backside conductive contact and a bottom of the gate stack. 
 
     
     
       2. The semiconductor device structure as claimed in  claim 1 , further comprising a metal-semiconductor compound layer between the backside conductive contact and the second epitaxial structure, wherein the metal-semiconductor compound layer is in direct contact with the etch stop layer. 
     
     
       3. The semiconductor device structure as claimed in  claim 1 , wherein the etch stop layer contains nitrogen. 
     
     
       4. The semiconductor device structure as claimed in  claim 1 , wherein the second epitaxial structure is wider than the backside conductive contact. 
     
     
       5. The semiconductor device structure as claimed in  claim 1 , further comprising:
 a dielectric filling laterally surrounding the backside conductive contact, wherein the etch stop layer is between the backside conductive contact and the dielectric filling. 
 
     
     
       6. The semiconductor device structure as claimed in  claim 5 , further comprising:
 an isolation structure laterally surrounding the dielectric filling and the backside conductive contact. 
 
     
     
       7. The semiconductor device structure as claimed in  claim 6 , wherein the backside conductive contact is in direct contact with the isolation structure. 
     
     
       8. The semiconductor device structure as claimed in  claim 6 , wherein the dielectric filling is separated from the isolation structure by the etch stop layer. 
     
     
       9. The semiconductor device structure as claimed in  claim 6 , wherein the dielectric filling extends past interfaces between the first epitaxial structure and the channel structures. 
     
     
       10. The semiconductor device structure as claimed in  claim 6 , wherein the backside conductive contact is in direct contact with the isolation structure and the etch stop layer. 
     
     
       11. A semiconductor device structure, comprising:
 a stack of channel structures; 
 a first epitaxial structure and a second epitaxial structure sandwiching the channel structures; 
 a gate stack wrapped around the channel structures; 
 a backside conductive contact connected to the second epitaxial structure, wherein the backside conductive contact is below a bottom surface of the second epitaxial structure; 
 a dielectric filling laterally surrounding the backside conductive contact; and 
 an isolation structure laterally surrounding the dielectric filling and the backside conductive contact. 
 
     
     
       12. The semiconductor device structure as claimed in  claim 11 , wherein the backside conductive contact is in direct contact with the isolation structure. 
     
     
       13. The semiconductor device structure as claimed in  claim 11 , further comprising:
 a nitride layer between the dielectric filling and the backside conductive contact. 
 
     
     
       14. The semiconductor device structure as claimed in  claim 13 , wherein the backside conductive contact is in direct contact with the isolation structure and the nitride layer. 
     
     
       15. The semiconductor device structure as claimed in  claim 11 , wherein the second epitaxial structure extends past opposite edges of the backside conductive contact. 
     
     
       16. A semiconductor device structure, comprising:
 a stack of channel structures; 
 a first epitaxial structure and a second epitaxial structure sandwiching the channel structures; 
 a gate stack wrapped around the channel structures; 
 a backside conductive contact connected to the second epitaxial structure, wherein the backside conductive contact is below a bottom surface of the second epitaxial structure, and the second epitaxial structure extends past opposite edges of the backside conductive contact; and 
 a dielectric filling laterally surrounding the backside conductive contact, wherein the first epitaxial structure extends past opposite edges of the dielectric filling. 
 
     
     
       17. The semiconductor device structure as claimed in  claim 16 , further comprising:
 an isolation structure laterally surrounding the backside conductive contact and the dielectric filling. 
 
     
     
       18. The semiconductor device structure as claimed in  claim 17 , wherein the backside conductive contact is in direct contact with the isolation structure. 
     
     
       19. The semiconductor device structure as claimed in  claim 17 , further comprising:
 a first dielectric fin and a second dielectric fin stacked over the isolation structure, wherein the second epitaxial structure is between the first dielectric fin and the second dielectric fin. 
 
     
     
       20. The semiconductor device structure as claimed in  claim 19 , wherein the first dielectric fin is taller than the backside conductive contact.